Sunday's Gospel (John) is known as the Cleansing of the Temple. Here are the basics - after making a whip out of cords, drives the money changers out of the Temple, overturning their tables and pouring their money out on the ground. For a feast that's all about building something (the Dedication of the Basilica marking the end product of a massive construction project), this outburst of destruction by Jesus looks like an odd choice for a reading.
After all, this feast is all about the Pope's cathedral, the place that the faith flows from. So what does one of the most violent episodes in Jesus' life have to do with the dedication of the mother church for Rome and for the world? For the answer, look at what Jesus says while he's driving them out.
Coupled with what Jesus actually says (listen for the Gospel on Sunday, or use the URL below), Jesus' actions in driving the money changers out of the Temple fit perfectly with the imagery of the river - moving, active and dangerous, changing and shaping everything it touches. More on this tomorrow.
Readings for Sunday: http://www.usccb.org/bible/readings/110914.cfm